CVE-2026-31234: Horovod Contains an Insecure Deserialization Vulnerability
Affects horovodSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 27 Oct 2026, 17:30 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIhorovod | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, restrict network access to the KVStore HTTP server to trusted entities only and consider disabling or isolating the KVStore component to prevent unauthorized HTTP PUT requests.
Description
Horovod versions up to 0.28.1 contain a critical insecure deserialization vulnerability in the KVStore HTTP server component. This component lacks authentication and authorization, allowing remote attackers to write arbitrary data via HTTP PUT requests. The KVStore server deserializes data using cloudpickle.loads() without verifying its source, enabling attackers to execute arbitrary code remotely by sending malicious pickle payloads.
References
- nvd.nist.gov/vuln/detail/CVE-2026-31234 (opens in a new tab)
- github.com/horovod/horovod (opens in a new tab)
- github.com/pypa/advisory-database/tree/main/vulns/horovod/PYSEC-2026-354.yaml (opens in a new tab)
- pypi.org/project/horovod (opens in a new tab)
- notion.so/CVE-2026-31234-35d1e139318881d585cde508b9d2453c (opens in a new tab)